How FAST simulate the isolated rotor in a vacuum?

I want to simulate the isolated rotor modes wherein the tower-nacelle subsystem is fully rigid. I want to check the case, for an isolated rotor spinning in a vacuum, progressive and regressive modal frequency curves are symmetric about the corresponding collective modal frequency curve.

When I do this simulation, I just change the feature flags in the .fst file. I enable FlapDOF1, FlapDOF2, and EdgeDOF, and disable TeetDOF, DrTrDOF,GenDOF, YawDOF, TwFADOF1,TwFADOF2,TwSSDOF1,TwSSDOF2,CompAero and CompNoise.

and keep all of other parameters unchanged, then do the linearizaiton.

Is this simulation correct? Has anyone done this case before?


Kuangmin Gong

Dear Kuangmin Gong,

We have done this linearization many times before. The input specifications you explain are correct.

In order to calculate the collective, progressive, and regressive modal frequencies, you must process the FAST linearization output with the MBC3 code, which is availabe here:

I hope that helps.

Best regards,